The photographs from Simmons camera confirm Mischu's opinion that a white man committed the murder. The air police set off in their two planes to track him down, and both parties are successful. Biggles discovers that a training camp near to the Ethiopian border, and Algy locates the murderer himself, but when Algy turns his machine back to rendezvous with Biggles he and his companions are surprised to see native soldiers moving about the strip...